56 THE SPIRIT OF THE SOIL 



treated Melilotus gave 23 per cent, heavier crop than 

 untreated. At Aberdeen, " on a farm where the 

 soil is peaty, and clover had never grown well, the 

 treatment has been remarkably successful, producing 

 a thicker covering of clover and a much stronger 

 growth. The difference has increased between 

 October and the present time in an extraordinary 

 way." 



Even before the Board of Agriculture Report had 

 appeared, in the autumn of 1905, American experi- 

 menters had discovered a cause of failure. The 

 bacteria when sent out on dried cotton-wool only 

 retained their vitality for a period of from six weeks 

 to a couple of months, a fact that in itself amply 

 explained the negative results obtained in many of 

 the experimental stations in this country. For it 

 was admitted that in several instances the cultures 

 had been kept as much as six or eight months before 

 being applied to the land. 



While Amferica was carrying out field experiments 

 on this lavish scale with cultures of the Bacillus 

 radicicola, the attempt was being made by Professor 

 Bottomley in the Botanical Laboratories of King's 

 College, London, to clear up several points that were 

 obscure in the life history of the bacteria, and to 

 determine accurately the nature of the chemical 

 changes involved. When the Board of Agriculture 

 discontinued their field experiments he decided to 

 invite the co-operation of farmers, professional 

 growers, and others interested, to test the efficiency 

 of the pure cultures with which he had been working 

 at King's College. To send out the bacteria on 



